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Main Authors: Nakamura, Hiroaki, Shiraishi, Densuke
Format: Preprint
Published: 2022
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Online Access:https://arxiv.org/abs/2210.17182
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author Nakamura, Hiroaki
Shiraishi, Densuke
author_facet Nakamura, Hiroaki
Shiraishi, Densuke
contents The Galois action on the pro-$\ell$ étale fundamental groupoid of the projective line minus three points with rational base points gives rise to a non-commutative formal power series in two variables with $\ell$-adic coefficients, called the $\ell$-adic Galois associator. In the present paper, we focus on how Landen's functional equation of trilogarithms and its $\ell$-adic Galois analog can be derived algebraically from the $S_3$-symmetry of the projective line minus three points. Twofold proofs of the functional equation will be presented, one is based on Zagier's tensor criterion devised in the framework of graded Lie algebras and the other is based on the chain rule for the associator power series. In the course of the second proof, we are led to investigate $\ell$-adic Galois multiple polylogarithms appearing as regular coefficients of the $\ell$-adic Galois associator. As an application, we show an $\ell$-adic Galois analog of Oi-Ueno's functional equation between $Li_{1,\dots,1,2}(1-z)$ and $Li_k(z)$'s $(k=1,2,...)$ .
format Preprint
id arxiv_https___arxiv_org_abs_2210_17182
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Landen's trilogarithm functional equation and $\ell$-adic Galois multiple polylogarithms
Nakamura, Hiroaki
Shiraishi, Densuke
Number Theory
11G55, 11F80, 14H30
The Galois action on the pro-$\ell$ étale fundamental groupoid of the projective line minus three points with rational base points gives rise to a non-commutative formal power series in two variables with $\ell$-adic coefficients, called the $\ell$-adic Galois associator. In the present paper, we focus on how Landen's functional equation of trilogarithms and its $\ell$-adic Galois analog can be derived algebraically from the $S_3$-symmetry of the projective line minus three points. Twofold proofs of the functional equation will be presented, one is based on Zagier's tensor criterion devised in the framework of graded Lie algebras and the other is based on the chain rule for the associator power series. In the course of the second proof, we are led to investigate $\ell$-adic Galois multiple polylogarithms appearing as regular coefficients of the $\ell$-adic Galois associator. As an application, we show an $\ell$-adic Galois analog of Oi-Ueno's functional equation between $Li_{1,\dots,1,2}(1-z)$ and $Li_k(z)$'s $(k=1,2,...)$ .
title Landen's trilogarithm functional equation and $\ell$-adic Galois multiple polylogarithms
topic Number Theory
11G55, 11F80, 14H30
url https://arxiv.org/abs/2210.17182